Jessica, 27, will be maid of honor at her 23-year-old sister’s wedding to rocker Pete Wentz. A source close to Jessica tells PEOPLE that Romo will be attending the event with Jessica.

Getting a head start, on Friday Jessica and Romo met for lunch at Katsuya in Hollywood. The Dallas Cowboys quarterback, dressed casually in shorts and sneakers, arrived at the restaurant in a cab for the lunch with Simpson, who wore a sexy black short-shorts and high heels. He greeted the singer with a kiss and helped her out of her Range Rover.